Coordinate measuring machines of the aforesaid type are known, comprising a base provided with guides along which a first horizontal X axis, a first carriage mobile on the base along the X axis and comprising an upright provided with guides extending along a second vertical axis, a second carriage carried by the upright and sliding on the same along Z axis, and an arm carried by the second carriage and extending along a third horizontal Y axis orthogonal to the X axis. One end of the arm is adapted to carry a contact or optical detector for measuring dimensional features of parts.
For the purpose of maintaining the second carriage balanced, the machines of the aforesaid type are generally provided with a counterweight secured to the second carriage by means of a belt and sliding within the upright.
More specifically, the upright is internally provided with vertical guides along which the counterweight moves.
This solution entails high manufacturing costs because the upright must be machined with the due accuracy, generally made by extrusion, to obtain the resting surfaces for the guides, and due to the cost of the guides.